Transmission polarizer

Abstract

The invention relates to a device for changing the polarization of an incident electromagnetic wave. Existing devices to change the polarization of an incident electromagnetic wave preserve signal decoupling, i.e., the relation between useful polarization and cross-polarization of the incoming signal. Furthermore, known prior art devices are far too big for many applications. The aim of the inventive device is to improve signal decoupling. During transmission of an electromagnetic wave through the transmission polarizer, the cross-coupled fraction of an incoming signal is greatly reflected thus leading to improved decoupling of the transmitted signal. Furthermore, the transmission polarizer can be manufactured in the form of a single planar printed board. The transmission polarizer is particularly useful to change the polarization of an incident electromagnetic wave, i.e. from linear to circular polarization or vice versa, and to rotate the polarization of an incident electromagnetic wave around a fixed angle.

What is claimed is:  
     
       1. A device for changing the polarization of an incident electromagnetic wave comprising: 
       a planar dielectric printed circuit board with a front side, a substrate and a back side; and  
       a plurality of homogeneously distributed strip conductor structures disposed on the front and back sides of the printed circuit board where the printed circuit board is composed of an array of elementary cells, each elementary cell including one said strip conductor structure on the front side of the printed circuit board, one said strip conductor structure on the back side of the printed circuit board which is disposed opposite the one said front side strip conductor structure and the substrate of the printed circuit board between the one said front and one said back side strip conductor structures;  
       wherein, each front side strip conductor structure has two main axes (x, y) disposed in a plane on the front side of the printed circuit board, each back side strip conductor structure has two main axes (ξ, ψ) disposed in a plane on the back side of the printed circuit board, and, in each elementary cell, the respective main axes of the one said front and one said back side strip conductor structures are angled relative to one another by a predetermined angle greater than zero.  
     
     
       2. The device according to claim  1 , wherein at least one of each individual strip conductor structure on the front side of the printed circuit board has a different geometry in each direction of the two main axes (x, y), and each individual strip conductor structure on the back side of the printed circuit board has a different geometry in each direction of the two main axes (ξ, ψ). 
     
     
       3. The device according to claim  2 , wherein the front and back side strip conductor structures have the form of one of rectangles, crosses and ellipses. 
     
     
       4. The device according to claim  1 , wherein, in each elementary cell, if the one said front and one said back side strip conductor structures are circumscribed by polygons, the front and back strip conductor structures are disposed in such a way that projections of the circumscribed polygons onto the plane of the front side of the printed circuit board intersect one another. 
     
     
       5. The device according to claim  1 , wherein, in each elementary cell, the one said front and one said back side strip conductors are disposed in such a way that projections of the front and back side strip conductors onto the plane of the front side of the printed circuit board intersect one another. 
     
     
       6. The device according to claim  5 , wherein, in each elementary cell, the projection of the intersecting point of the main axes (x, y) of the strip conductor structure of the front side of the printed circuit board onto the plane of the front side of the printed circuit board coincides with the projection of the intersecting point of the main axes (ξ, ψ) of the strip conductor structure of the back side of the printed circuit board onto the plane of the front side of the printed circuit board. 
     
     
       7. The device according to claim  1 , wherein at least one of: all of the strip conductor structures of at least one side of the printed circuit board have the same form and the same dimensions; and all of strip conductor structures of at least one side of the printed circuit board have uniform distances from one another in at least one direction. 
     
     
       8. The device according to claim  1  wherein the individual strip conductor structures of each side of the printed circuit board are aligned parallel to one another, and the individual strip conductor structures of each side of the printed circuit board are disposed symmetrically in relation to at least one axis disposed in the planar surface of the printed circuit board. 
     
     
       9. The device according to claim  8 , wherein at least one of the individual strip conductor structures of each side of the printed circuit board are disposed collaterally in rows that extend perpendicularly to each other, and the individual strip conductor structures of each side of the printed circuit board are disposed in a radially symmetrical manner. 
     
     
       10. The device according to claim  1 , wherein the device includes a number of dielectric printed circuit boards each said printed circuit board being disposed with their flat sides parallel to one another, one behind the other. 
     
     
       11. The device according to claim  10 , wherein the printed circuit boards are disposed one behind the other in a congruent fashion. 
     
     
       12. The device according to claim  6 , wherein the device has only one planar dielectric printed circuit board, the individual strip conductor structures of each side of the printed circuit board are aligned parallel to one another, and the individual strip conductor structures of each side of the printed circuit board are disposed symmetrically in relation to at least two axes disposed in the planar surface of the printed circuit board in such a way that the individual strip conductor structures of each side of the printed circuit board are disposed collinearly in rows that extend perpendicularly to one another, and that the rows that extend perpendicularly to one other on one side of the printed circuit board respectively intersect in the center of a strip conductor structure. 
     
     
       13. The device according to claim  12 , wherein on the front side of the printed circuit board, the strip conductor structures have the form of rectangles (R 1 ) which have approximate edge lengths of 3.35 mm and 1.65 mm, 
       on the back side of the printed circuit board, the strip conductor structures have the form of rectangles (R 2 ) which have approximate edge lengths of 0.50 mm and 3.05 mm,  
       the rows of the front side strip conductor structures, which are disposed parallel to the first symmetry axis of the front side of the printed circuit board, have an average distance (A) of approximately 4.0 mm,  
       the rows of back side strip conductor structures, which are disposed parallel to the second symmetry axis of the front of the printed circuit board, have an average distance (B) of approximately 5.2 mm, and  
       in each elementary cell, the one said front and one said back side strip conductor structures are disposed in such a way that the two main axes (x, y) of the front side strip conductor structure, which are disposed in the plane of the front side of the printed circuit board, and the two main axes (ξ, ψ) of the back side strip conductor structure, which are disposed in the plane of the back side, are respectively angled in relation to one another by a predetermined angle that is approximately 33 degrees, the substrate of the printed circuit board having a thickness of approximately 1.57 mm and permittivity of approximately 2.33.  
     
     
       14. The device according to claim  8 , wherein the front side strip conductor structures have the form of rectangles (R 1 ) which have approximate edge lengths of 2.76 mm and 1.38 mm, 
       the back side strip conductor structures have the form of rectangles (R 2 ) which have approximate edge lengths of 0.30 mm and 2.58 mm,  
       the rows of front side strip conductor structures, which are disposed parallel to the first symmetry axis of the front side of the printed circuit board, have an average distance (A) of approximately 4.74 mm,  
       the rows of back side strip conductor structures, which are disposed parallel to the second symmetry axis of the front side of the printed circuit board, have an average distance (B) of approximately 3.01 mm, and  
       in each elementary cell, the one said front and one said back side strip conductor structures are disposed in such a way that the two main axes (x, y) of the front side strip conductor structure, which are disposed in the plane of the front side, and the two main axes (ξ, ψ) of the back side strip conductor structure, which are disposed in the plane of the back side, are respectively angled in relation to one another by an angle of approximately 32 degrees, the substrate of the printed circuit board having a thickness of approximately 1.52 mm and a permittivity of approximately 2.5.  
     
     
       15. A use of a device according to claim  1  to change the polarization of an incident electromagnetic wave from linear polarization into circular polarization or vice versa. 
     
     
       16. A use of a device according claim  1  to rotate the polarization of an incident electromagnetic wave by a fixed angle. 
     
     
       17. The use according to claim  16 , wherein the fixed angle is approximately 90 degrees.